1. Field of the Invention
This invention relates to a tooling pin assembly used to position an object in a reference position, and particularly, a tooling pin assembly which allows an operator to adjust manually the position of a locating pin in the assembly to compensate for minor irregularities of test sites on the object or in the fixture, or both.
2. Background Discussion
It is common practice to test circuit boards using a bed of pins type test fixture such as illustrated in U.S. Pat. Nos. 4,340,858 and 4,701,703. The circuit boards are relatively flat, planar structures which have a number of test sites at different locations on the board's surface. The bed of pins type test fixture has probes which engage these test sites during testing. Electrical current is passed through the probes and test sites, and passes through an electronic analyzer to determine if the circuits on the boards are constructed properly.
The probes are mounted on a lid assembly, and the circuit board is positioned on a flat platen so that the test sites and the tips of the probes are in registration and make physical contact during testing. There are locating holes in the perimeter of the circuit board, and stationary locating pins mounted along the perimeter of the platen which pass through these holes when the circuit board is placed on the test platen. This positions the test sites on the circuit board in registration with the probes. Sometimes there are minor irregularities in the circuit board or the test fixture, so that the probes do not properly engaged the test sites and either miss the test sites or contact a corner rather than the center of the test sites. These minor irregularities do not prevent the board from functioning, but only prevent reliable testing of the board. Minor irregularities result from art work shifts, solder mask encroachment on the test sites, fixture assembly errors, negative accumulation of dimensional tolerances, etc.